Cardiovascular fitness and physical activity in children with and without impaired glucose tolerance

Objective: To examine differences in cardiovascular fitness (VO _2max) and physical activity levels in overweight Hispanic children with normal glucose tolerance (NGT) vs impaired glucose tolerance (IGT). Participants: A total of 173 overweight (BMI percentile 97.0±3.1) Hispanic children ages 8-13 years with a family history of type 2 diabetes. Methods: VO_2max was measured via a maximal effort treadmill test and open circuit spirometry. Physical activity was determined by questionnaire. Glucose tolerance was established by a 2-h oral glucose challenge (1.75 g of glucose/kg body weight). IGT was defined from an oral glucose tolerance test as a 2-h plasma glucose level ≥140 and <200mg/dl. Results: IGT was detected in 46 of the 173 participants (∼27%); no cases of type 2 diabetes were identified. No significant differences were found between youth with NGT and those with IGT in absolute VO_2max (2.2±0.6 vs 2.1±0.5 l/min), VO_2max adjusted for gender, age, and body composition (2.2±0.2 vs 2.1±0.2 l/min), or recreational physical activity levels (8.7±8.2 vs 6.9±6.2 h/week). Conclusion: Overweight Hispanic youth with IGT exhibit similar levels of VO_2max and physical activity compared to their NGT counterparts. Longitudinal analyses are necessary to determine whether fitness/activity measures contribute significantly to diabetes risk over time in this group.